While a variety of materials and methods have apparently been used to provide a light-diffusion layer upon the surface of the glass envelope employed in electric lamps, the predominant technique has been a deposit of fine-size silica coatings upon the glass substrate which has been etched prior to coating. The light scattering effect produced with a low bulk density silica coating applied upon the interior surface of the bulb wall in incandescent lamps is described in U.S. Pat. No. 2,922,065 to Meister et al, which also mentions various methods of applying this general type of coating. Less effective light-scattering materials which are also mentioned in this patent are alkaline-earth and manganesium titanates, oxides, alumina, titania, and zirconium silicate. Of the 150 different finely divided light-scattering materials said to have been experimentally investigated, none were found as efficient as the low bulk density silica. The problems still encountered with low bulk density silica coatings, however, are reported in a later U.S. Pat. No. 2,963,611 which issued to one of the same inventors and these problems were said to be ameliorated by either adding a material having a true density of at least about 4 grams/cm.sup.3 to the silica or by precoating the glass substrate with this more dense material prior to deposition of the silica coating. While the improvements thereby attained are said not to reduce the light-scattering properties of the overall light-diffusion medium, it will be apparent that such additional means increases the cost and difficulties of achieving the final result. Consequently, improved coatings having more effective light-scattering properties and which can be applied more simply are still being sought.